vb.net - 让标签显示文本框的相反长度？

Question

在 Visual Basic 中，我做了一个标签来显示文本框的长度，现在如何让它显示你在文本框中还剩下多少个字符？我的意思是在 Twitter 上，你如何限制这么多字符。我也想要它，这样当它达到 10 或更低时，标签变成红色，然后超过 10，标签变成黑色。如果问题不应该出现在这个论坛中，请原谅我，我只是不知道如何做到这一点。

Answer 1

在 Windows 窗体中，您可以编写

 label1.Text = (textBox1.MaxLength - textBox1.Text.Length).ToString();

Answer 2

The above answer has an error because it is trying to convert a decimal to a string, so you need to wrap that in brackets and call .ToString() as for your colours idea I used percentages. If you have used more than 50% and less than 75% of your character allowance, then make the text orange. If you have used more than 75% then make it red.

  lblRemaining.Text = string.Format("{0} characters remaining", (textBox1.MaxLength - textBox1.TextLength).ToString());
  decimal percentageUsed = ((decimal)textBox1.Text.Length / (decimal)textBox1.MaxLength) * 100;
  if (percentageUsed >= 50 && percentageUsed < 75)
    lblRemaining.ForeColor = Color.Orange;
  else if (percentageUsed >= 75)
    lblRemaining.ForeColor = Color.Red;
  else
    lblRemaining.ForeColor = Color.Green;